How to get dual graphic cards working under Linux?

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http://unix.stackexchange.com – My laptop is Dell Inspiron 5420, with two graphic cards: Intel HD Graphics 4000 Nvidia GeForce GT 630M I took the Thinkpad T400 configuration guide as an example to configure my Linux, but I only get the integrated card to work, and the card is not using the Intel driver Currently, the behavior of my system is: using the intel driver in the Xorg.config, X cannot starts, reports cannot find the device using the vesa driver, the X could work, but no advanced graphic features, which means Gnome 3 is not available using the nvidia / nouveau driver, according to the log, the X seems to be st (HowTos)